Not for individual buildings, no. If I'm allowed to think I'm really good at one thing, then it's always knowing exactly where I am and where I'm trying to go. In other words, I guess I kind of understand spacial relationships and direction intuitively that way. So, no. I keep all that stuff stored in my brainmeat just fine.

Maps and city layouts though? I'm awful with that and still struggle with making them look right in really really wide shots.

Generally, the more thought you put in your comics, the better. Planning buildings (as in making real plans for them) is good to avoid logic mistakes later on. But in all honesty, I think in most cases, the reader won't value stuff like that very highly. Or even recognize it.
As for my comic, stuff like that isn't even nessecary, but as a general rule I'd say, you have to see, how much effort you put into one thing and how much it will contribute (visibly) to your comic.

I made a floorplan once because it was part of the joke, but I haven't referenced it since then. It started out looking like my first floor, but then I started moving things that weren't conveniently located.